Recessed double contact pin base



e 25, 9 w. B. LANDGRAF 3,430,139

RECESSED DOUBLE CONTACT PIN BASE Filed May 15, 1967 hwvervtov: WiLLiamB. Landgva' f ba @425 His A t to neg United States Patent York Filed May15, 1967, Ser. No. 638,398 US. Cl. 339-14 5 7 Claims Int. Cl. H01133/74, 9/08, 5/04 ABSTRACT OF THE DISCLOSURE An electric lamp base has adisk-shaped insulating body provided with a hollow embossment and a pairof spaced apart, inlead wire accommodating, hollow contact pins stakedto and recessed within the embossed portion of the insulating body. Eachpin has at its outer end an eyelet for connection to an inlead wirethreaded through the pin, a rectangular portion in cross sectionextending longitudinally from said eyelet and, prior to being staked onthe insulating body, a deformable tubular portion extendinglongitudinally from the rectangular portion and terminating in an opendome-shaped end. The rectangular portion of each pin is supported onthree sides by the embossment, the fourth side being exposed withinembossment for engagement with a lamp holder contact.

BACKGROUND OF THE INVENTION Field of the invention Bases having contactsrecessed within an embossed, disk-shaped insulating body for safetypurposes have been in extensive use for more than ten years ondouble-ended electric lamps, such as tubular fluorescent dischargelamps, of the type having preheatable electrodes mounted at the ends ofa tubular glass envelope and a pair of spaced-apart current inlead wiresfor each of the electrodes extending from the ends of the envelope.

Description of the prior art Heretofore, the current inlead wiresextending from the ends of the lamp envelope have been recessed andexposed within the hollow embossment of the insulating base body forutilization as the lamp terminals or contacts. Also, contacts welded tothe inlead wires and in the form of strips of various configurationshave been used similarly. Outwardly projecting exposed contact pins onthe lamp bases thus were eliminated.

Fluorescent electric discharge lamps having bases provided withterminals or contacts of the above type are disclosed in US. Patents2,716,739, Lemmers; 2,733,420, Marz; 2,733,421, Grovemiller; and2,922,137, Krupp et al.

In the mass production of lamps equipped with such bases, properlyinserting, orienting and afiixing the contacts in the insulating body ofthe base has been accomplished with some difficulty. If the contacts aremisplaced, become loosened or displaced during manufacture or use of thebased lamp to the extent that the base contacts fail to engage the lampholder contacts, the lamp fails to operate. 7

SUMMARY OF THE INVENTION The principal object of the invention is toprovide a lamp base of the above type readily manufactured at minimumcost including novel contacts which are easily I 3,430,189 Patented Feb.25, 1969 mounted and firmly supported in proper position for effectiveengagement with electric socket or lamp holder contacts. The inventionattains its object by utilizing as the contacts a pair of hollow pinswhich in part are rectangular in cross section and fit into cavitieswithin the hollow embossment with one side of the rectangular portionexposed for engagement with a lamp holder contact. Each pin has atubular portion for insertion into an opening in a wall at the bottom ofthe hollow embossment for staking the pin to the wall and an eyelet atits outer end for connection to a lamp inlead wire threaded through thepin aind welded or soldered to the eyelet.

BRIEF DESCRIPTION OF THE DRAWING In the drawing accompanying and formingpart of this specification, an embodiment of the invention is shown inwhich:

FIG. 1 is a side elevational view of a double-ended electric dischargelamp provided with bases embodying the invention;

FIG. 2 is a fragmentary sectional view of an enlarged scale of one endof the based lamp shown in FIG. 1;

FIG. 3 is a plan view of the base shown in FIG. 2 as seen from the innerend of the base facing the end of the lamp envelope;

FIG. 4 is a similar view of the base shown in FIGS. 2 and 3 as seen fromthe outer end of the base;

FIG. 5 is a view similar to FIG. 4 showing a fragment of the insulatingpart of the base with the contact pins removed to show the internalstructure of this part of the base; and

FIG. 6 is an isometric view on an enlarged scale of one of the hollowmetal contact pins of the base embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 of thedrawing in which like numbers denote like parts in all the figures, thedouble-ended fluorescent electric discharge lamp comprises a tubularsealed glass envelope 1 provided with bases 2 and 3 attached to itsends. The bases 2 and 3 are of identical structure and the parts only ofthe base 3 have been shown in FIGS. 2 to 6 for conciseness indescription.

The base 3 comprises an annular metal shell 4 which is suitably made ofsheet aluminum and a body member of electrically insulating material,such as an organic plas tic, in the form of an embossed disk 5. The disk5 may be made of commercial plastic molding compounds, such as thosecomprising phenol-furfural resins or phenolic resins. The inner rim ofthe shell 4 is embedded in the periphery of the insulating disk 5 tomechanically join these base members as shown in FIGS. 2 to 4. The baseis secured to the end of the glass envelope by a body of basing cement6.

The disk 5 has a raised elongated embossment 7 fiattened in crosssection, extending across its center and projecting outwardly from thebase (FIGS. 1, 2, 4 and 5) for engagement with a holder (not shown) forthe lamp. The embossment 7 has straight parallel sides and rounded endsin cross section (FIGS. 4 and 5). The em bossment 7 is hollow anddefines an inwardly extending slot 8 terminating at the wall 9 providedwith a pair of openings 10 and 11. The slot 8 conforms generally t thecross sectional shape of the embossment 7, accommodates the electricalcontacts of the lamp holder (not shown) and has recesses 12 and 13 atits opposite ends accommodating the rectangular portions 14 and 15 ofthe hollow contact pins 16 and 17, respectively. One side of theportions 14 and 15 of the pins is exposed within the slot 8 forengagement with a lamp holder contact.

The hollow contact pins 16 and 17 are aflixed to the embossed disk asdescribed below and define wiring passages through which the inleadwires 18 and 19, respectively, of the lamp are threaded during lampmanufacture. The inlead wires 18 and 19 are electrically connected toopposite ends of the preheatable electrode 20 and extend through thepress 21 of the stem 22 of the lamp envelope 1. In the completed lampthe wires 18 and 19 extend through the pins 16 and 17 of the base 3, asshown in FIG. 2, and are electrically connected by soldering or weldingto the integral eyelets 23 at the outer ends of the pins 16 and 17.

As shown in FIGS. 2, 4 and 5, three sides of the rectangular portions 14and 15 of the pins 16 and 17 make a close fit with the walls of therecesses 12 and 13, respectively, in opposite ends of the slot 8 in theembossment 7. This provides firm support against forces tendlng torotate the pins 16 and 17 axially or to move the rectangular portions 14and 15 away from each other laterally as the contact pins are engagedwith or disengaged from the spring-mounted contacts of a conventionallamp holder.

As shown in FIGS. 2, 3 and 5 of the drawing, the pins 16 and 17 areaffixed to the disk 5 by their tubular portions 24 which, in themanufacture of the base, are first passed through the slot 8 andinserted into the openings and 11 of the wall 9 and then upset againstthe wall 9 to hold the inner end of the rectangular portions 14 and ofthe pins 16 and 17 firmly against the opposite side of the wall 9. Thetubular portions of the contact pins 16 and 17 have an opening 25 atthelr outer ends to facilitate the cutting and spreading thereof in theform shown at 26 in FIG. 3. This is conventional and a well knownoperation in the lamp base making art. With the pins 16 and 17 affixedto the base in this manner the eyelets 23 at the outer ends of the pinsare recessed within the outer end of the slot 8 as shown in FIG. 2. Thewidth of the slot 8 is such that the eyelets cannot be touched whenmounting the lamp in lamp holders. As shown in FIGS. 2 and 4, the outerends of the pins and the surfaces of the rectangular portions 14 and 15thereof exposed within the slot 8 are readily accessible for engagementwith contacts of the lamp holder in the usual manner.

The inlead wires 18 and 19 extending from the ends of the lamp envelope1 are easily threaded into the hollow pins 16 and 17 of the bases 2 and3 for connect on by soldering or welding to the eyelets 23 to facilitatethe manufacture of the lamp. Reference is made to US. Patent 2,892,923,R. A. Kuebler, for a disclosure of a method and apparatus useful inWelding the ends of the inlead wires to the eyelet of each contact pin.

The exposed longitudinally extending surfaces of the rectangularportions 14 of the pins and the eyelet ends of the pins provide contactsurfaces of large area for engagement by the lamp holder contacts whichare accommodated within the slot 8 when the lamp 1 is mounted in theconventional lamp holders. I

The sides of the rectangular portions 14 of the plus are larger in widththan the outer diameter of the tubular portions 24 thereof so that theshoulder 27 is provided on the pins for engaging the Wall 9 as shown inFIG. 2.

The pins may be made in the shape described above by folding a suitableblank cut from a metal strip, brass for example, around a mandrel intothe form shown in FIG.

The disk 5 has a vent 28 in the wall 9 for fluids resulting from curingof the basing cement 6. The vent 28 flares outwardly toward the back ofthe base to assure adequate spacing between the exhaust tip 29 of thelamp envelope 1 and the base mounted on the envelope.

While a preferred species of the invention has been disclosed, it willbe understood that such disclosure is for illustrative purposes and thatit is contemplated that changes may be made in the form and details ofthe base without departing from the invention as defined in the appendedclaims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A base for attachment to an electric lamp envelope having a pair ofoutwardly extending inlead wires, said base comprising an electricallyinsulating body member in the form of a disk having an elongated hollowembossment flattened in cross section and extending outward from the"base for engagement with a lamp holder, said embossment having a lampholder contact-receiving outwardly opening slot conforming generally tothe shape of the embossment and provided with base contact receivingrecesses at its opposite ends, said body member having an apertured wallat the bottom of the slot, said base comprising also a pair of hollowcontacts for connection to said inlead wires, said hollow contacts beinglaterally recessed within the ends of the embossment, affixed to theapertured wall and fitting into the recesses at the ends of the slotwith a lateral side thereof exposed for engagement with lamp holdercontacts.

2. A base according to claim 1 wherein the exposed side of the hollowcontacts presents a flat surface of substantial area for engagement withlamp holder contacts.

3. A base according to claim 1 wherein the recess fitting portion of thehollow contacts is rectangular in cross section.

4. A base according to claim 1 wherein the hollow contacts have at theirouter ends an inlead wire-accommodating eyelet and define a wiringpasage into the eyelet opening.

5. A base according to claim 1 wherein the hollow contacts are staked tothe apertured wall with the recess fitting portion thereof engaging thesurface of the wall facing the slot.

6. A base for attachment to an electric lamp envelope having a pair ofoutwardly extending inlead wires, said base comprising an electricallyinsulating body member in the form of a disk having an elongated hollowembossment flattened in cross section and extending outward from thebase for engagement with a lamp holder, said embossment having a lampholder contact receiving outwardly opening slot conforming generally tothe shape of the embossment and provided with base contact receivingrecesses at its opposite ends, said body member having an apertured wallat the bottom of the slot, said base comprising also a pair of hollowcontacts for connection to said inlead wires, said hollow contacts beinglaterally recessed within the ends of the embossment, each of saidhollow contacts being in the form of a hollow pin having at its outerend an inlead Wire accommodating eyelet, a portion rectangular in crosssection extending longitudinally from the eyelet and fitting into therecesses at the ends of the slot with a lateral side thereof exposed forengagement with lamp holder contacts, a deformable tubular portionextending longitudinally from the rectangular portion and definingtherewith a wiring passage into the eyelet opening, said deformabletubular portion extending in part through an opening in the aperturedwall and being upset in part against the surface of the wall facing awayfrom the slot, the rectangular portion of the pin engaging the surfaceof the apertured wall facing the slot.

7. A hollow contact pin having at one end an inlead Wire-accommodatingeyelet, a socket-contact engaging ortion rectangular in cross sectionextending longitudinally from the eyelet and a deformable tubularportion extending longitudinally from the rectangular portion anddefining therewith a wiring passage into the eyelet opening, the sidesof the rectangular portion being larger in width than the outer diameterof the tubular portion to 5 provide between said portions 21 supportengaging shoulder.

References Cited UNITED STATES PATENTS 1,559,683 11/1925 Douglas 3392201,888,165 11/1932 Gagnon 339--195 2,438,075 3/1948 Smith 339-220 Orr339-145 Schwarz 339- 220 X Thomas 339-145 Pechy 339--145 U.S. C1. X.R.

